In recent years, as information technology has progressed, techniques related to storage media that store information in form of electronic data have advanced rapidly. Among the storage media, a large-capacity storage medium such as a magneto-optical disk and a magnetic tape is often used for data backup by using the large storage capacity. In particular, when data on ever-changing information such as transaction information of banks and securities is continuously backed up, the amount of data for backup (backup data) to be generated is enormous. In such a case, generally, large-capacity storage media are used, backup data is written into the storage media, and the storage media storing the backup data are kept. Here, conventionally, a library device has been known as a device suitable for managing such a large amount of backup data, and various kinds of library device have been proposed in Japanese Patent Laid-open Publications No. 2000-222039, No. H10-64144, No. S61-292262 and No. S61-73267.
The library device includes: plural cells each containing a storage medium, a drive accessing the contained storage medium (writing and reproducing data), and a robot transferring the storage medium between the drive and the cells. The robot includes a housing section that houses the storage medium. The robot retrieves a desired storage medium from the cell and houses the storage medium in the housing section. Subsequently, the robot transfers the housed storage medium to the drive, and returns the storage medium to the cell by transferring the storage medium again, after the storage medium is accessed by the drive. In this way, in the library device, a large amount of data is sequentially written into the storage media and kept in the plural cells and thus, management of a large amount of backup data is efficiently carried out.
Here, in many of conventional library devices, cells and a drive are fixed to a frame (part of a housing) such that the orientation (the way of placing) of a storage medium contained in each cell and the orientation (the way of placing) of a storage medium contained in the drive are the same. As the orientation of the cells and the drive, generally, either a horizontal orientation or a vertical orientation is adopted according to the way the storage medium is placed.
FIG. 1 and FIG. 2 are diagrams each illustrating an example of the arrangement of cells and drives in a conventional library device.
FIG. 1 is a diagram that illustrates an example of the arrangement of cells and drives in a conventional library device 100′ that employs the horizontal orientation, and FIG. 2 is a diagram that illustrates an example of the arrangement of cells and drives in a conventional library device 200′ that employs the vertical orientation.
In the arrangement of FIG. 1, the horizontal orientation is adopted as the way of placing a storage medium 1. FIG. 1 illustrates the storage medium 1 contained in each of four of cells 2 in the horizontal orientation and the storage medium 1 housed in a housing section 3a of one of drives 3 in the horizontal orientation, within a frame 101′. In this way, to be matched with the horizontal orientation adopted as the way of placing the storage medium 1, the cells 2 and the drives 3 are disposed in the horizontal orientation.
On the other hand, in the arrangement of FIG. 2, the vertical orientation is adopted as the way of placing a storage medium 1. FIG. 2 illustrates the storage medium 1 contained in each of four of cells 2 in the vertical orientation and the storage medium 1 housed in a housing section 3a of one of drives 3 in the vertical orientation, within a frame 201′. In this way, to be matched with the vertical orientation adopted as the way of placing the storage medium 1, the cells 2 and the drives 3 are disposed in the vertical orientation.
In either of the arrangement in FIG. 1 and the arrangement in FIG. 2, a not-illustrated robot retrieves a desired storage medium from the cell, houses the retrieved storage medium in the housing section, transfers the housed storage medium to the drive, and returns the storage medium to the cell by transferring the storage medium again after the storage medium is accessed by the drive, so that backup data is managed efficiently.
In recent years, in the field of library device, a standardized frame available on the market has been adopted as a frame of the library device, and members and units such as cells, drives and a robot have been disposed within the frame, in many cases. In a case in which the standardized frame is thus adopted as the frame of the library device, when the cell and the drive are disposed in the same orientation, wasted space may be formed.
For example, in the arrangement of FIG. 1, within the frame 101′, there is space 5 on the left side in FIG. 1. This space 5 is so small in the width in a lateral direction in FIG. 1 that it is difficult to dispose the cells 2 and the drives 3 in the space 5 in the horizontal orientation. Also, in the arrangement of FIG. 2, within the frame 201′, there is space 5′ on the lower side in FIG. 1. This space 5′ is so small in the width in a vertical direction in FIG. 2 that it is difficult to dispose the cells 2 and the drives 3 in the space 5′ in the vertical orientation.
In the field of library device, demand for a library device that holds a large amount of information without a large device volume is growing, and an idea of arranging cells and drives densely so that storage media are accommodated as many as possible within a limited device volume is desired. When there is wasted space like the space 5 in FIG. 1 and the space 5′ in FIG. 2, it is difficult to realize such a high-density arrangement.
It is conceivable to densely arrange the cells and the drives by mixing the vertical orientation and the horizontal orientation of the cells and the drives, and separately provide the robot with a function of changing the orientation of the housing section by using a drive system that employs a motor to meet such a mixture of the orientations. However, when such a drive system is provided, a control system for controlling this drive system is desired to be newly added, which may lead to an increase in cost.